This invention relates to a measuring device for measuring and setting various parameters related to a cyclist""s riding position on a bicycle.
To a performance cyclist, the fit of a bicycle, like the fit of a runner""s shoes, is very important. Changes as small as one centimeter to the relative positions of the saddle, handlebars, or pedals can have a dramatic affect on the rider""s performance, comfort, enjoyment and risk of injury. The more advanced and highly trained the rider, the more important precise fit becomes. Accordingly, a great deal of effort is expended achieving proper fit.
Ironically, after a particular bike has been adjusted to a particular rider, whether by painstaking trial-and-error or, as the product of a fitting session, it is not easy to replicate that riding position on another bike. Instead, riders and bike mechanics make adjustments by eye or feel, or use an unwieldy collection of levels, rulers, strings and straightedges, or a combination thereof. These efforts are at best time-consuming and demand substantial skill in order to achieve acceptable results, and are often imprecise and fruitless.
Individually these tools are easy to use. However, adjusting the fit of a bicycle frequently requires two or more dimensions to be tracked simultaneously. For example, although no generally agreed upon coordinate system for bicycles exists, the following four measures are common: vertical height of the saddle above the bottom bracket called xe2x80x9csaddle height,xe2x80x9d the vertical distance between the saddle and handlebars, called xe2x80x9cdrop,xe2x80x9d the distance of the saddle""s nose behind the bottom bracket, called xe2x80x9csetback,xe2x80x9d the horizontal distance between the saddle and handlebars, called xe2x80x9cnose to bars.xe2x80x9d However, since the saddle is raised and lowered by sliding the post to which it""s attached in or out of a non-vertical seat tube, moving the seat post in or out changes both the x and y components of its location, i.e., moving the seat xe2x80x9cupxe2x80x9d also moves the seat back, and vice versa. Referring back to the earlier defined measurements it""s clear that adjusting xe2x80x9cseat heightxe2x80x9d also changes the values of xe2x80x9cnose to bars,xe2x80x9d xe2x80x9cdrop,xe2x80x9d and xe2x80x9csetbackxe2x80x9d.
In 1956, prolific bicycle industry innovator Tullio Campagnolo developed a jig-like device for setting saddle position. A photo of this can be seen on page 136 of Greg LeMond""s Complete Book of Bicycling (ISBN 0-399-13229-5). The device is largely unknown in America, perhaps because in 1956 the American market for high-end bikes was virtually non-existent.
Examination of the picture shows that its object was to simultaneously integrate the vertical height of the saddle, the horizontal position of the saddle with respect to the bottom bracket, and the angle of the saddle with respect to the horizontal. These features if nothing else would simplify adjustments, because repositioning a saddle to align with a jig is clearly easier than repositioning a saddle by manually re-measuring between each approximation. However, along with these advantages, examination of the photo reveals limitations that would prevent its use on many modern bicycles, and shortcomings, which if overcome, would improve its usefulness on any bicycle.
First, said device was attached to the bike by means of a rigid clamping structure adapted to clamp to the top tube, and was held perpendicular to the top tube. Since all top tubes at the time were level, round and exactly 1xe2x85x9xe2x80x3 in diameter, this arrangement would have been somewhat satisfactory. However, many if not most modern racing bicycles are made with top tubes whose diameters are larger than 1xe2x85x9xe2x80x3, and/or whose cross-sections are complexly non-circular, and/or whose cross-sections vary complexly along the tube""s length, and/or which are not level, i.e., the device could not be attached to many of today""s bicycles at all.
Second, it appears that the device doesn""t incorporate its own consistent measuring system. As earlier mentioned, it was apparently more jig than measuring device.
A further consequence of not providing a measuring system and indexing off the top tube is that when moving the device to different bikes, even those of the day, the jig itself would usually need to be readjusted and calibrated before the bike could be adjusted.
Additional study of the problems involved in bike fitting show that changing the length of a bicycle""s cranks changes the xe2x80x9creachxe2x80x9d of a rider""s legs to touch the pedals, as does changing to different cycling shoes and/or different pedal systems. The combined impact of these differences can range from zero to an inch or more, the latter figure being one that all but the most position-insensitive cyclists would find objectionable if not painful and possibly injurious. Typically, when changing to components with different vertical dimension components, cyclists adjust the numeric value used to describe their correct position rather than changing the point from which they measure. Thus, typical measuring equipment and techniques fail to adequately deal with riding position quantification as a function of the rider""s anatomy.
Therefore, it is an object of the present invention to provide a device which may be used to measure the riding position on any bicycle, and which may be adjusted so as to act as a jig to accurately guide the adjustment of a bicycle to a desired riding position.
It is another object of the present invention that all dimensions be measured in relation to a coordinate system incorporated in said invention, rather than in relation to the repositionable components themselves.
It is still another object of the present invention to provide a method and means whereby said device factors out variations in crank length, shoe sole thickness, or pedal system height, so that a measured riding position xe2x80x9cheightxe2x80x9d remains the same for that rider regardless of variations in these components.
Moreover, it is yet another object of the present invention to provide a method and means whereby said device may be rapidly and easily attached to and aligned with and used on a bicycle without necessitating disassembly of said bicycle.
In addition, it is another specific object of the present invention that the device be alignable with a bicycle""s bottom bracket without removal of the crank or crank fixing bolts of the bicycle.
Further, it is yet another object of the present invention that said method and means of attachment and alignment not be affected by the size, shape, cross-section, or angular relationship of a bicycle""s tubes.
The device of the present invention measures position height, saddle setback, saddle angle, reach, and bar angle in relation to a vertical reference line extending upwardly from the center of the bottom bracket, and parallel to the vertical, horizontal, and longitudinal planes of the bike.
xe2x80x9cPosition Heightxe2x80x9d is the vertical distance from the insole of the rider""s shoe to the intersection of the vertical reference line and a line extended across the top of the saddle (the xe2x80x9csaddle linexe2x80x9d).
xe2x80x9cSaddle Setbackxe2x80x9d is the distance from the intersection of the vertical reference line and the saddle line (the xe2x80x9cintersection pointxe2x80x9d) to the back of the saddle measured along the saddle line. Other arbitrary reference points on the saddle could be used instead of the back.
xe2x80x9cSaddle Anglexe2x80x9d is the angle between the vertical reference line and the saddle line.
xe2x80x9cReachxe2x80x9d is the distance from the intersection point to the top center of the handlebar""s tubular cross section at a point along the handlebar""s width where said handlebars are approximately perpendicular to the longitudinal plane of the bike when the front wheel is pointing straight ahead. Other arbitrary reference points on the handlebar could be used instead of the top center.
xe2x80x9cBar anglexe2x80x9d is the angle between the vertical reference line and a line extended from the intersection point to the top center of the handlebar.
A key element of the present invention is that said device can measure position height as defined above without connecting to any part of the bicycle below the bottom bracket. This is accomplished by offsetting the gradations of the vertical scale by an amount equal to xe2x80x9ca phantom crank/shoe/pedal,xe2x80x9d then physically shifting the position of the vertical scale by the amount needed to alter the effective length of the xe2x80x9cphantom crankxe2x80x9d to match any probable actual crank, shoe, and pedal combination.
Another key element of the present invention is a crank adaptor, which can align itself with the commonly used crank fixing bolts. By providing a hole on the device of the present invention to admit said crank adaptor at the desired reference point, said reference point is thus aligned with the bottom bracket of any bike without necessitating the removal or loosening of the crank fixing bolt or crank. The design of the crank adaptor accomplishes the preceding in a manner which prevents the crank fixing bolt from applying rotational forces to the crank adaptor or visa versa, which would otherwise greatly complicate attachment or use of the device.
The device of the present invention consists of two primary physical modules, a support section and a measuring section, which is attached to said support section.
Said support section is fashioned as two vertical parts, slidably connected to and aligned with each other by means of a clamping mechanism, which vertical division permits the aforementioned compensation adjustments to be made. The uppermost of the two vertical parts is marked with a vertical scale. Said reference unit also incorporates a crank adapter which aligns the device with the bottom bracket, and provides the two means by which said device is attached to a bike, the first of which is a hook and loop strap located near the crank adaptor.
The second attachment means constitutes a key element of the present invention because it allows said device to be slidably attached to bike top tubes of any probable shape, dimension, cross-section or angular displacement. In addition, because said second attachment means attaches said upper portion slidably, said support section can be shifted forward or backward with respect to said vertical reference line while stably attached, thus providing the means whereby both gross and minute vertical adjustments to said support section can be made. Said second attachment method further provides the means whereby said support section can be made parallel to both the longitudinal and vertical axes of the bike.
Said measuring section consists of a longitudinal measuring component aligned and calibrated to quantify the linear distance at any point upon said longitudinal measuring component""s length from the point where said longitudinal measuring component""s linear axis intersects said vertical reference. Said longitudinal measuring component further incorporates a gauge for convenient determination of the exact point along said longitudinal measuring component""s length to which said linear distance is to be measured. Said longitudinal measuring component is attached to said measuring section in a fashion which allows it to measure linear distances both in front of and behind said vertical reference line with respect to the longitudinal axis of the bicycle. In addition, the longitudinal measurement component can be offset with respect to the centerline of the bike while remaining parallel to said centerline; which allows said longitudinal measuring component to avoid aspects of a bicycle which would otherwise prevent measurements, and further allows said longitudinal measuring component to better interact with the upper surfaces of a saddle.
Said measuring section also incorporates a gauge which quantifies the angular relationship of said longitudinal measuring component with said vertical reference. Furthermore, said measuring section is attached to said support section by a third attachment means which includes a means of quantifying the vertical position of said measuring section along said vertical reference. In addition, said third attachment means attaches said measuring section to said support section in a manner which permits said measuring section to be slidably or fixedly positioned with respect to said support section.